Expression And Analysis Of PDGF And CDYL Genes In Testis Of The Chinese Red Steppe Cattle At Different Months

Chinese red steppe cattle has the advantages of early sexual maturity,good production performance and strong stress resistance.It is an excellent breed with the potential to produce snowflake beef.Breeding bulls are the important part of the breeding population and they play an important role in the process of improving the genetic performance of beef cattle population.The meat line of Chinese red steppe cattle formed by crossbreeding with Angus cattle has achieved remarkable results in the production of high-grade beef.Breeding bulls provide a large amount of high-quality semen for the production of beef cattle so that good genetic traits are stably inherited.So ideal reproductive performance is essential for breeding bulls.Testis is an important organ of spermatogenesis.Normal testicular development is the basis of excellent reproductive performance of breeding bulls.There is a great significance that exploring the genetic mechanism and molecular regulation mechanism of bull testicle development.Spermatogenesis is the selection and breeding of high-yield and high-quality breeding bulls.Testicular development and spermatogenesis depend on the precise regulation of related genes,while PDGF and CDYL genes may regulate the development of testes.Therefore,the study selected Chinese grassland red bulls as the research object to observe the changes of testicular structure and the expression of PDGF and CDYL in testicular tissues at different ages(1,12,18 and 24 months),in order to find the correlation between testis development and spermatogenesis during sexual maturity of Chinese red steppe cattle,and to analyze the genetic basis of testicular development in cattle from a molecular perspective.The relative expression levels of spermatogenesis-related genes PDGF and CDYL proteins and m RNA in testicular tissues were detected by immunohistochemistry and real-time fluorescence quantitative technology,which provided basic data for exploring the molecular regulation and transcriptional regulation mechanisms of spermatogenesis and testicular somatic cell development in bulls.The main results of this study are as follows:1.Histological characteristics of HE staining and paraffin section observation of testicle tissue of Chinese red steppe cattle showed that the diameter of the spermatogenic tubule in the testis at the age of 1 month was small,and no seminomyte development and differentiation were seen;At the age of 12 months,the size and structure of the testis endospermatogenous tubule has been stabilized,and the seminomynia cells in the testis of the 12～24 months old grassland red bull have active differentiation and development,which is the key period for the reproduction and development of the grassland red bull bull.2.The immunohistochemical tests of CDYL and PDGF genes in testicles of different months of age showed that CDYL and PDGF genes had positive reactions in supporting cells,mesenchymal cells,primary spermatocytes and secondary spermatocytes in testes of different months-old prairie red bull,but there were great differences in the positive reaction values of the two genes in terms of integrated optical density.The integral optical density value of PDGF gene was significantly higher than that of other months age group(P<0.05)at 1 month age,and the integral optical density value of CDYL positive reaction was significantly higher than that of other age groups at 24 months(P<0.05).The production of the two results may be related to the difference in the regulatory mechanism of the two genes in the testes.3.RT-PCR test of CDYL and PDGF genes in testis of steppes red bull at different months showed that the expression levels of CDYL and PDGF genes were basically consistent with the expression trend of positive integrated optical density value.CDYL gene was not expressed in testis at 1 month of age,while PDGF gene expression level was significantly higher than that in other months of age groups(P< 0.05).CDYL gene expression was found in testicular tissue at12 months of age and increased from 12 months to 24 months of age,with the highest expression level at 24 months of age and 12 months of age significantly different(P < 0.05).The expression of PDGF gene in testis decreased gradually from 12 to 24 months,and the expression level was the lowest at 24 months.This may be related to the regulation of PDGF gene on spermatogonial stem cells,sertoli cells and sertoli cells in testis of low age.